Steam-engine



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A. STEPHENS. STEAM ENGINE.

(Application led Sept. 13, 1898.)

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Y Patented May 9, |8991.

No. 624,700. Patented May 9, |899. A. STEPHENS STEAM ENGKNE.

(Application filed Sept. 13, 1898.)

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UNITED STATES PATENT OFFICE.

'ALEJANDRO STEPHENS, OF GUADALAJARA, MEXICO..

STEAMiENGINE.

SPECIFICATION forming part of Letters Patent No. 624,700, dated May' 9,1899.

Application filed September 13, 1898. Serial No. 690,846. (No model.)

To all whom it may concern: y

Be it known that I, ALEJANDRO STEPHENS, of Guadalajara, Mexico, haveinvented new and useful Improvements in Steam-Engines, of which thefollowingis a full, clear, and exact description.

My invention has for its object to provide a steam-engine which will besimple in construction, reliable in operation, capable of great speed,and economic in the use of steam.

To this end I construct the steam-en gine as fully describedhereinafter.

The novel features of my invention will be particularly pointed out inthe claims.

Reference is to be had to the accompanying drawings, forming a part ofthis specification, in which similar characters of reference indicatecorresponding parts in all the gures.

Figure l is a sectional elevation of my improved engine on line l l ofFig. 3 with the piston in its lowermost position. Fig. 2 is a similarview with the piston at the end of the upstroke, and Fig. 3 is a sideelevation of the engine with part of the cylinder and its cap or shellin section.

A is the frame of the engine, in which is journaled the main shaft B andwhich carries the cylinder C. In the cylinder is arranged to move thepiston D, connected by the piston-rod E and the connecting-rod F to acrank G on the shaft B.

The piston D comprises two parts of different diameters and practicallyforming two pistons. The inner section D is tted to slide upon the outersurface of a central body C', secured at the bottom of the cylinder C.At a point adjacentto the upper end of the section D' when the `pistonis in its lowermost position the top plate C2 of the cylinder and thecentral body C are provided with packin g-rings H, adapted to engage thepiston-section D upon its inner and its outer surfaces. During itsupstroke the piston-section D moves into a chamber I, formed by anupward extension C8 of the cylinder C. This extension has an opening C4connected to the steamsupply. The outer section D2 of the piston isannular and surrounds the cylindrical portion of the piston-section D atthe bottom thereof.- This outer section D2 moves in the annular chamberI', contained` between the cylinder C and the central body or core C andmust be provided with'a packing-ring, such as I-I. plate C2 issurrounded by a cap or shell J, forming a closed chamber I2, which bymeans of apertures G5 in the top plate C2 communicates with the chamberI. The central body or core C of the cylinder has a partition C(idividing it into a central chamber I3 and an outer annular chamber I4communicating by means of apertures C7 in the partition C6. yThe centralchamber 1200mmunicates at the bottom with the exhaust-pipe K and is openatthe top (see Fig. 2) to the'chamber I5, inclosed by the piston-sectionD' during its-upstroke. Near its top the chamber I2 has an annulargroove C8, into which projects an annular rib C9, having apertures C0,by means of which the said groove may communicate with the chamber I3proper. At the bottom the chamber I2 has channels C10 leading outwardlyinto the chamber I'. At the top the chamber I2, or rather the groove C8,is in permanent communication by means of an opening C11 with theworking chamber I5 of highpressure cylinder D.

Within the chamber I3 are located two cutoff valves, one of which, L, isdouble,having two pistons or heads L L2, of which the upper piston Lcontrols the passage of steam through the ports CO-that is, from theworking chamber I5 into the receiver formed by the chambers I3 I4. Thelower' head L2 is adapted to connect the ports C10 (and thus the workingchamber of the annular lowpressure cylinder) alternately with the eX-hau'st-pipe K and with the receiver I3 I4.` The Y other valve L3 isadapted to move in a guide or small cylinder D2, having apertures D4leading into the space formed by the annular groove C8.

tion is established between the steam-chamber I and the interior of thecylinder D3. These apertures D5 are adapted to be throttled by a ring M,seated upon a concave surface at the top of the piston D and capable ofturning on said surface with the pistonrod E as its axis. The ring M ispressed downward by a spring N' and has radial slots M', adapted tocover or uncover the apertures D5. trolled by a governor O, operatedfrom the The extension@3 above the top The top of the piston D'4 hasapvertures D5, by means of which a communica- IOO The position of the ringM is con- Y shaft B by bevel-wheels P P and connected with the ring M bymeans of a rod Q, a bellcrank lever R, fulcrumed at R', a connecting-rodS, a lever T, fulcrumed at T, and a connecting-rod U, whose ends areconnected by ball-and-socket joints with one end of the lever T and withthe free end of an arm M2, rigidly secured to the ring M.

The cut-off valve L3 for the high-pressure cylinder l5 is operated bymeans ot' a sleeve V, mounted to slide on the piston-rod E and pivotallyconnected with rods W, operated by a couple ,of eccentrics B on theshaft B.

y Similarly the valve LL2 for the low-pressure cylinder is operated bythe sleeve X,mounted to slide on the'sleeve V and connected by rods .Ywith the eecentrics Bzaon the shaft B.

It will be seen that the valve L2 is au admission and exhaust valve forthe low-pressure cylinder, and the valve L is at the same time anexhaust-valve for the high-pressure cylinder and an admission-valve forthe receiver, while the valve L3 is a cut-ott valve for thehigh-pressure cylinder and the ring M forms a variable cut-oii,depending upon the speed of the engine.

It will be understood 'that the relative location of thevalves,eccentrics, Vand crank will be such as to secure the propertiming of the valves, as will be described presently.

1When the compound piston is at the end of the downstroke, Fig. 1, steamfrom the chamber l passes through the slots M and apertures D5 into thecylindrical chamber D3 and through the apertures D4 into the groove CB,the aperture C, and the working chamber I5 of the high-pressure pistonD', thus equalizing the pressure on both faces of said piston. At thesame time steam,which during the downward stroke has passed from thehigh-pressure working chamber liinto the receiver I3 I4, is allowed (byan appropriate movement of the valve L2) to pass through the channelsG10 below the annular low-pressure piston D2, driving thev same upward.Thus during the Vupstroke only the low-pressure piston is active. Theair above the lowpressure piston instead of being compressed within thechamber I (which would cause a considerable resistance as the proachesthe top plate C2) is driven out through the apertures C5 into thechamber I2, and owing to the large area of the two chambers l I2 thedegree of compression and the resistance due thereto are only slight.The advantage of having the apertures C5 lead into a closed chamber l2instead of making them open into the surrounding air resides in the factthat the Vbod y of air passing alternately in and out through theapertures C5 remains the sam-e and can have no cooling action on thepiston and steam.

As the compound piston finishes the upstroke, Fig. 2, the valve L2 isshifted to cut off the receiver I3 I4 from connection with the workingchamber of the low-pressure cylinder and to connect said working chamberpiston apwith the exhaust-pipe K. rThe pressure is A haust from thehigh-pressure cylinder passes into the receiver. Vmoving above theapertures D4 cuts the Finally the valve L3 by working chamber lr ottfrom connection with the steam-chamber l. There will therefore be apreponderance of pressure on the upper surface of the high pressurepiston D', whether the valve-ring M be in the open position, Fig. 1,orthe closed position,l*`ig. 2. Thus the piston D will be forced downward.During the downstroke only the high-pressure piston will be active. Itwill be seen that while each of the pistons is single-acting the engineis double-acting.

The cut-off ring or valve M will, it is understood, become operativeonly in case the engine exceeds a predetermined speed, when said valveMwill cut off steam from the highpressure working chamber l5 during theupstroke before the piston-valve L3 closes the apertures D, and when thevalve M closes the openings D5 during the upstroke the preponderance ofsteam-pressure on the upper surface of the high-pressure piston D willcheck the upward movement of the piston.

It will be understood thatmodilications, as long as they remain withinthe scope of the appended claims, will constitute no departure from thenature of my invention.

Having thus described my invention, l claim as new and desire to secureby Letters Patentf l. A high-pressure piston, an annular lowpressurepiston surrounding the high-pressure piston and rigidly secured thereto,the high-pressure piston having a passage leading from one face thereofto the opposite face, a cut-oit valve controlling said passage, acylinder having two chambers in which said pistons move, a receiverhaving a valve-controlled connection with the working chamber of thehigh-pressure cylinder, the low-pressure cylinder havingl av channelleading to the receiver and to the exhaust, and a valve for opening saidchannel to the receiver, when the high-pressure piston is vat the end ofits working stroke, and for connecting said channel with the exhaustwhen the high-pressure piston is at the end of its inactive stroke, andmeans for actuating the valves, substantially as described'.

2, The combination of the annular low- IOO IIO

pressure cylinder, the receiver located cenl trally within the saidcylinder, the high-pressure cylinder located substantially in axialalinement with the receiver, the low-pressure piston movable in thelow-pressure cylinder, the high-pressure piston mounted to slide on theoutside of the receiver, valves controlling 'the connections of thereceiver with the high- 624,700 l g Y a pressure cylinder and theW-pressure cylinder, and the connection of the latter With the exhaust,substantially as described.

3. The combination of the single-acting cylinder, the piston therein,the cylinder having at one end a channel for the alternate admission andescape of the driving agent, a steamchamber adapted to communicate withsaid channel, a valve controlling said communication and a closedchamber in permanent communication with the other end of the cylinderand separated at all times from the steam-receiving end of the cylinder.

4. The combination of the high-pressure cylinder, the low-pressurecylinder, the 10W- pressure piston, the high-pressure piston having apassage leading from one face thereof to the opposite face, a valvecontrolled directly from the engine-shaft to close said passage at apredetermined period of the stroke, a variable-cut-off valve carrieddirectly by one of the pistons and likewise arranged to close saidpassage, a speed-controlled governor operatively connected With saidvariable-cut -oft valve, and connections from the high-pressure cylinderto the low-pressure cylinder, substantially as described.

5. The combination of the high-pressure cylinder, the receiver, thelow-'pressure cylinder, the pistons in said cylinders, the highpressurepiston having a passage leadingzfrom one face thereof to the oppositeface, and the receiver having passages by Which it may communicate witheither of the cylinders, a piston-rod connected With one 'of thepistons, valves controlling said passages and provided With sleeves oneof which slides on the pistonrod, While the second valve-sleeve slideson the one first mentioned, and means for actu- ALEJANDRO STEPHENS.

Witnesses:

LUIS lldormivinivl, V. HUBER.

